Study On Preparation,Crystal Structure And Magnetic Properties Of Ions Doped YFeO₃

Yttrium ferrite（YFeO₃）is a kind of classical perovskite ferrite of ABO3 type.It has the properties of high resistivity,fast domain wall movement and high antiferromagnetic transition temperature.It has a good prospect in the fields of magnetic sensors,microwave devices and optical position measurement.The application of YFeO₃ is greatly influenced by its magnetic properties,so researchers are committed to improving the magnetic properties by ions doping of YFeO₃ and the preparation of its composite materials.In this paper,pure phase Eu³⁺ and Nd³⁺ doped YFeO₃ samples were prepared by sol-gel method.The crystal structure and magnetic properties of the samples were characterized by X-ray diffraction（XRD）,scanning electron microscopy（SEM）,infrared spectroscopy（FTIR）and vibrating sample magnetometer.The effects of the above methods on the structure and properties of YFeO₃ were studied.The main conclusions are as follows:1.When the calcination temperature was 650℃,the hexagonal phase YFeO₃ was synthesized.The hexagonal phase and the orthogonal phase YFeO₃ existed simultaneously with the temperature increased.The pure orthogonal phase YFeO₃ was synthesized at 900℃.The crystal size of orthogonal phase YFeO₃ powder is larger than that of hexagonal phase.Orthogonal phase YFeO₃ also has higher agglomeration.The complete hysteresis loop diagram can be obtained with applied magnetic field at 6T.2.When YFeO₃ is single doped with ion,all the samples are pure phase orthogonal YFeO₃ powders.Ions randomly occupy the lattice position of Y³⁺ in YFeO₃ structure.With the increase of doping amount,the lattice constant of the powder increases.The larger the doping ion radius is,the larger the increase of the lattice constant is.With the increase of doping concentration,the saturation magnetization of YFeO₃ increases and the residual magnetization decreases.At the same doping concentration,the larger the ion radius,the larger the saturation magnetization and the smaller the residual magnetization.3.When YFeO₃ is double doped with ions,all the samples are still pure phase orthogonal YFeO₃ powders.The main diffraction peaks move to a low theta angle,and the crystal lattice parameters increase with the increase of the ion concentration with a larger radius.The grain growth of the double doped powder is more sufficient,which has a complex effect on the tensile vibration of B-O bond and the bending vibration of O-B-O in the BO6 octahedron.Controlling the concentration of one ion,the higher the concentration of the other ion with larger diameter,the greater the increase of saturation magnetization.The doping ions may interact in the process of replacing the lattice position,which makes the magnetic parameters change disorderly and irregularly.